Chris Anderson,
Right on!
What niether of you are working out is weather the timing spec is for degrees of advance when the "protrusions" are in-line with the ports, or when the "groove" is in-line with the ports.
That is what I'm trying to get to with Don. I was trying to take small steps towards that very topic. Don seems to think if the dial indicator is in the groove then the timing is more retarded than if it is measured from the protrusion. But the fact is that has nothing to do with it. The answers to your questions are in the timing charts.
Don,
You're good at repeating yourself and saying nothing at the same time. Do you remember talking to me at Speedworks at the first dyno day we had there? Do you remember talking about timing pumps and uncomfortable you were with the procedure? Do you remember telling me that if you moved the dial indicator just a little, the reading would jump up and down? I thought you knew even back then that the tip of the indicator is riding up and down the protrusions as the dial indicator is moved.
Yes, the timing tools center the dial indicator in the bore, but the gauge can be wiggled to ride the plunger at different locations.
Don, yes I bought a 913 pump. Cord also got a 913 pump. I'm not going to put words in Cord's mouth, but I can speak for myself. I felt conned. I too had heard that the pump advanced timing. That's definately something I wanted. You can imagine my surprise when I popped off the DV's and saw that timing is retarded from the idle setting as rack travel increases. That was definately a shocker to me. I was told I would be able to pull higher rpm without the annoying popping of the small pump. I COULDN'T. I was told it wouldn't have the 1200 rpm stumble associated with the 370's. IT DOES.
The funny thing is we are both working on setting up our small pumps to put back on. But you don't know that yet. Another 'interesting' tidbit of info was Piers calling me and telling me to not get rid of my small pump because we will use it later. But you didn't know that either.
Animal,
FYI, my personal pump (913) retards the timing from the idle position for starting purposes and then advances the timing at idle.
-Chris